its not mandatory as in its a hardfork or anything but it includes all of the latest GETH commits. 130 of them to be exact.

"This release fixes an issue where some clients could get stuck during a chain reorganisation and can happen at random. Without this fix you'd need to restart your client.

We haven't received any reports of this actually happening but noticed that one of our own (very long) running nodes got stuck."

-- Jeff Wilcke